Electrical contact



Jan. 20,1942.

ELECTRICAL CONTACT Filed June 9, 1939 Patented Jan. 20, 1942 UNITED STATES PATENT OFFICE 2,270,727 announcer. CONTACT Clarence T. Evans, Wauwatosa, Wis, assignor to Milwaukee, Wis., a cor- Cutler-Hammer, Inc. poration of Delaware Application June 9, 1939, Serial No. 278,208

3 Claims.

possible so that their operation does not materially affect the response of the switch to the effect of its operating means. Furthermore the auxiliary switches should be easily and accurately adjustable and maintain their adjustment indefinitely, and they should close and open their circuits in a definite and reliable manner.

. An object of the present invention is to provide an auxiliary switch of the aforementioned kind which is provided with contact surfaces which prevent the accumulation of dust which would interfere with its successful operation.

Another object is to provide a switch which is readily modified so as to open and close in difsubject to chattering when opening or closing its circuit.

Another object is to provide a switch which may be operated with a minimum of power.

Other objects and advantages will hereinafter appear.

The accompanying drawing. is illustrative of an embodiment of the invention.

In the drawing.

Figure 1 is a side view of an auxiliary switch which is open when the electromagnetic switch with which it is used is open and which is closed upon closure of the electromagnetic switch.

Fig. 2 is a side view of an auxiliary switch similar to that shown in Fig. 1 except that the relation between the functioning of the electromagnetic switch and the auxliary switch is reversed.

Fig. 3 is an exploded view of part of the device shown in Figs. 1 and 2, while Fig. 4 is an exploded view of the removable contact element and its support of the switches shown in Figs. 1, 2 and 3.

ferent. desired relations relative to the main contacts.

Another object is to provide an auxiliary switch which is readily adapted to electromagnetic 'switches of different size and construction.

Another object is to provide for an auxiliary switch of the aforementioned character a contact which is easily and quickly removed and replaced. 7

Another object is to provide an auxiliary switch of few parts which are simple and inexpensive.

Another object is to provide an auxiliary switch which has along service life.

Another object is to provide an auxiliary switch which may be connected in circuit so as to provide for either a double or a single break in said circuit when the contacts are opened.

Another object is to provide contacts which require no flexible connectors for completing the circuit.

Another object is to provide contacts which are self-aligning.

Another object is to provide an auxiliary switch which is insulated in a simple but reliable manner from the other parts of the electromagnetic switch.

Another object is to provide an auxiliary switch which has little inertia and therefore is not Referring to Fig. 1, the same shows an operating lever or armature I of an electromagnetic switch (not shown) which is pivoted at 2 for oscillatory movement thereabout. The leve is provided with an extension 3 which provides a stop to limit the outward or clockwise movement of the armature lever I. A further extension 4 on the lever I is provided with a cylindrical pin 5 for engagement with the auxiliary switch as will be explained hereinafter.

The auxiliary switch is supported on an angle bracket 6, one limb of which is provided with a slot 1 for the reception of headed screws or bolts B by means of which the bracket may be adjustably fastened to an insulating base 9. The limb of the bracket 6 which extends at a right angle from the support 9 has attached to it by welding or any other suitable means a second angle bracket III. The end of the limb of bracket l0 which extends at a right angle to the bracket 6 is bent to form a semi-circular bearing II for an oscillating operating lever l2. The lever ll comprises two parallelside members i3 which are joined by a cross member l4 intermediate of their ends. At one end the side members are joined by a pin 15 which forms a pivot for an insulating roller l6 and which is held in position for rotation about its pivot by the side members l3.

The cross member i4 is preferably integral with the side members I3 and is provided with a downward extension H to which is riveted or otherwise fastened a contact carrier la. The

upper end of the contact carrier is extended inside of the side members and bent to form a pivot 19 which engages the bearing H to permit oscillation of the lever l2. A spring 20 is interposed between the horizontal limb of bracket l and cross member M, to bias the lever relative to the bracket and to provide for readily releasable engagement between the pivot l9 and the bearing II. The ends of the spring :20 embrace concentric bosses 2| and 22 on the bracket I l and crosspiece M respectively, to maintain the spring in position relative to the bracket and lever.

Near its lower end the carrier I8 is provided with two recesses 23 which are at opposite edges of said carrier to receive a contact shoe 2i. The

latter comprises a generally flat strip 25 which is provided at its center with two upstanding lugs 26 which are spaced so that they may freely slide in the recesses 23. Y Intermediate their ends the lugs are bent outward and again upward as shown at 21, the two parallel sides 21 being spaced so as to slide freely over the end of the carrier 18 which is wider than the distance between the lugs 26 where they join the strip 25. The extreme ends 28 of the lugs are bent inwardly and whenthe shoe is assembled with the carrier engage a flat biasing spring 29 which is fastened at one end to the extension l1 and which biases the shoe 2| toward the carrier I8. The carrier is provided opposite the center of the shoe with a ridge or pivot 30 about which the shoe can oscillate. It will thus be seen that when placed on the carrier the shoe 24 is slidingly and pivotally'held in the recesses 23. If it is desired to remove the shoe, the spring 29 is compressed thus permitting the shoe to slide the parallel sides 21 are opposite the edges of the carrier I8, whereupon the shoe may be drawn over the end of the carrier l8 and removed therefrom. The spring 29 is preferably provided with an arcuate boss 3| at the point where it normally downward until engages the bent-over ends 28 of the shoe to provide for reduction of friction and to permit the shoe to more readily adjust itself. The boss' is preferably the arc of'a circle whose center is at the apex of the ridge 30 when the spring is compressed upon engagement with the shoe.

The shoe is provided near the ends of the strip 25 with contact buttons 32 which are adapted to engage and bridge stationary contact studs 33 mounted on the panel 9 and to which circuits to be controlled by the switch may be connected. Additional circuit connections may be made to the bracket 6 by means ,of the screws 8, so that the switch may be used in different combinations as, for instance, a double break single pole or a three point single break switch.

As shown in Fig. 1, the switch is norma y biased to circuit closing position by the spring 20. If the arm 4 of the lever I now moves clockwise. the pin 5 ultimately engages the roller l6 and causes counter-clockwise rotation of the switch about the pivot ll--l9 to open the circuit between contacts 32 and 33. The moment at which the contacts are opened relative to the movement of the arm 4 may be varied to some extent by vertical adjustment of the bracket 8 and by varying the height of the bracket above the support 9. The dotted lines show the switch in the open position, when the roller is fully engaged by the pin 5.

In Fig. '2 the horizontal arm of bracket 8 is it when the contactor is deenergized. Upon deenergization of the contactor the pin 5 permits the roller to move clockwise until the contacts are closed. It would obviously also be possible to arrange the position of the roller l6 relative to the pin 5 in such a manner that the contacts are closed in both extreme positions of the pin and opened only momentarily while the pin travels from one to another extreme position during response of the contactor. I

What I claim as new and desire to secure by Letters Patent is: I

1. A contact shoe comprising, an elongated support having a pair of symmetrical recesses at opposite sides thereof and a linear raised abutment transverse to said support and intermediate of said recesses, a contact shoe adapted toengage said abutment and having two symmetrical rearward extensions, the inner end of said extensions being spaced to slidingly engage said recesses, another part of said extensions being spaced to slide over the end of said support and to engage a biasing spring, and a flat biasing spring interposed between said support and said extensions and provided with a curved abutment for engagement with said extensions to bias said shoe against said first named abutment and to permit it to oscillate thereabout and further to permit said extensions to slide over the end of said support for removal therefrom upon compression of said spring.

2. As an article of manufacture, a' carrier for arm having a knife edge pivot formed on one face thereof against which the rear surface of said contactor is adapted to bear, said contactor having portions thereof extending rearwardly and then inwardly to substantially surround said last mentioned arm, and spring means interposed of such length that the pin 5 engages the roller between said last mentioned arm and said in'-' wardly extending portions to yieldably and releasably retain said contactor in interlocked relation to said last mentioned arm and in bearing engagement with said knife edge pivot, said contactor and said last mentioned arm being cooperatively formed to limit the degree of relative pivotal movement of the former.

'3. An auxiliary contactor for an electromagnetic-switch or the like, comprising a bracket for mounting said contactor upon an insulating support and provided with an open pivotal bearing, a bell crank lever having a pivot element carried thereby and located adjacent to the meeting point of the two arms of said ball crank and adapted to engage said bearing, a roller rotatably supported at the free end of one arm of said lever and adapted for engagement by an operating element of saidswitch, a bridging contactor removablyv interlocked with the other arm of said lever adjacent to the free end of the latter, said last mentioned arm having a knife edge pivot formed on one face thereof against which the rear surface of said contactor is adapted to bear, said bridging contactor having portions means interposed between said last mentioned spring for biasing said pivot element into enarm and said inwardly extending portions to gag'ement with said bearing and said bridging yieldably and releasably retain said bridging concontactor into engagement with. said stationary tactor in interlocked relation to said last mencontacts, and to permit rotation of said lever to tion'ed arm and in bearing engagement withsa id I 5 disengage said bridging contactor from said staknife edge pivot, said contactor and said last tionary contacts upon engagement of said roller mentioned arm being ncooperatively iormed to by said operating element.

- limit the degree of relative pivotal movement of the former, a pair of stationary contacts, and a CLARENCE T. EVANS. 

